This invention relates generally to means for controlling the transfer of fluids through flexible conduits defining flow paths and particularly provides a pinch valve module which is capable of operating upon a plurality of flexible conduits in preprogrammed sequence and which may be combined with like valves to enable control of flow through an extensive array of flexible conduits.
Apparatus intended for the conduct of a plurality of chemical tests automatically upon a series of individual samples fed to the apparatus are well known to the art. Such automated analysis apparatus is utilized in the medical, biological and industrial fields for obtaining diagnostic and routine information for empirical, control and even research purposes. Problems which had been encountered in manually conducted tests gave rise to automated, or at least semi-automated, testing apparatus.
One considerable problem encountered in manually operated and in automated apparatus has involved minimal efficiency of earlier fluid transfer, i.e. liquid transfer, in such a manner as to provide quantitatively accurate dilutions and satisfactory physical transfer from one testing location to another without appreciable loss of precision, accuracy and the fluid itself. Another persistent problem has been encountered in switching from one fluid source to another. Fluid valves, such as check valves, have been used to control the direction of flow as well as the timing of such flow. Often, valves are employed which operate upon the flow of fluid through flexible conduit by pinching or compressing the conduit.
Valves such as disclosed and claimed in U.S. Pat. Nos. 8,882,899 and 3,932,065 have been successfully offered as solutions to the many problems encountered such as achievement of precision and accuracy in effecting transfer of fluids from one location to another with achievement of accuracy and precision. Sealing and/or seating problems previously encountered perhaps may have been caused by sediment buildup on the sealing mechanism. Lack of quick responsiveness and leakage were the result. Mechanical hysteresis or backlash caused by time delay in achieving operating in an opening and closing of the valve gave rise to lag in the reaction time between initial operation of the valve and the actual achievement of such action. Backlash allows additional fluid to pass causing error in volume dispensed. Backlash is unpredictable being due somewhat to back pressure applied to the valve to cause the valve to close, for example.
Many analytical systems require many individual fluid paths to be monitored and further, provide a plurality of flexible fluid conduit to effect and to define flow paths for transferring fluids for both delivery and control of other functions as well as for the performance of testing procedures. Pinch valves had to be provided for each of the flow paths, along with their solenoid drivers and controls, the valves functioning as check valves, flow control valves or the like.
It would be more advantageous both for economy and for efficient space utilization, to reduce the number of pinch valves needed and improved their efficiency. Further, if operation of these valves could be simplified so that they could be present without expensive controls, much advantage would result. Improved vesatility, if achievable, would also be of advantage. Modular valve arrays are desirable.
It would be highly advantageous to provide a pinch valve module capable of being functionally preprogrammed for automatic sequentially timed operation further capable of being computer interfaced.
If the valve module could be provided with means whereby the position of the valving means thereof could control the sequential operation of the testing apparatus, for example, considerable advantage could ensue.